This invention relates to monitoring the configuration of component feeders on a component placement machine.
Component placement is one of the most labor and data intensive operations in electronic board assembly. Current high speed component placement equipment can place up to 10,000 to 30,000 components per hour, depending on configuration, and can carry up to 1,000,000 or more individual components.
Surface mount components are typically supplied by component vendors as rolled tapes of components that must be loaded onto individual feeders, sometimes called component dispensing cartridges, that can then be mounted in corresponding feeder slots on the machine. These rolls of components (up to, in some cases, 10,000 or more components per roll) may be loaded onto the feeders either at a stock room or at the machine, and the loaded feeders then loaded into feeder slots.
Component placement machines can have many feeder slots (e.g., 150 or more), each accessible by a placement turret or other picking mechanism that picks individual components from the feeders in the slots and places them in particular locations on a printed circuit board, according to programmed instructions. For application flexibility, each feeder and slot is generally constructed to be compatible with many different components.
The physical arrangement of components, feeders and slots must be in accordance with the expected arrangement as programmed in the machine. Any error in the arrangement can cause a corresponding error in the placement of components on the board. In a high volume, low mix manufacturing environment, a component loading error can produce a high number of defective printed circuit boards in a short period of time. In a low volume, high mix environment the chance of component loading error increases because of frequent feeder manipulation for product change over.
To help eliminate loading errors, some have suggested placing bar code labels on individual feeders and slots and then scanning the feeder and slot labels with a hand-held scanner as the feeders are placed in the slots (i.e., before the machine begins its operation).
The invention features a system for guarding against some of the typical loading errors that can occur even with the most conscientious machine operators, as well as providing much-needed inventory and maintenance data.
According to one aspect of the invention, a apparatus for monitoring the configuration of component feeders is provided, for use in a placement machine having a series of feeder slots for holding the component feeders. The apparatus includes slot markers for installation on the placement machine to correspond to the feeder slots, feeder markers for installation on the component feeders of the placement machine, and a marker detector adapted to monitor the arrangement of slot markers and feeder markers in the machine while the machine is in operation.
The slot markers and feeder markers may be light-scannable labels, the marker detector including a scanner arranged to scan the slot markers and feeder markers.
Preferably, the marker detector is arranged to substantially simultaneously scan the slot marker of a given slot and the feeder marker of the feeder in (i.e., installed in) the given slot. The apparatus can be triggered to scan a given slot marker and corresponding feeder marker by the machine as the machine picks a component from the slot corresponding to the given slot marker. By xe2x80x9csubstantially simultaneouslyxe2x80x9d we mean within the same pick cycle.
The marker detector, in some embodiments, is adapted to compare the arrangement of slot markers and feeder markers to stored data while the machine is placing components. The apparatus preferably also includes means to alert an operator (e.g., an audible or visible alarm) upon detection of an undesirable arrangement of slot markers and feeder markers.
The apparatus may be adapted to work with different types of placement machines. For example, for use with a placement machine that includes a moving picking mechanism and a stationary feeder platform, the scanner is preferably constructed to be attached to the moving picking mechanism of the placement machine. For use with a placement machine that includes a rotatable picking mechanism, a moving feeder platform and a stationary portion, the scanner is preferably constructed to be attached to the stationary portion of the placement machine.
The apparatus includes, in preferred embodiments, a data storage device adapted to store component feeder configuration data. The data storage device may be adapted to record the number of components remaining in each component feeder, and/or to track the number of times a given component feeder has been accessed by the placement machine.
The apparatus may also be adapted for use with multiple placement machines. In such configurations, the apparatus should include a data link between the multiple placement machines and the data storage device, preferably such that the data storage device may be constructed to update component feeder information from the multiplicity of placement machines.
The apparatus may be configured for use with component reels with light-scannable labels, also including a loading scanner adapted to scan the reel labels and feeder labels as the reels are mounted upon the feeders to identify which component is loaded on a given feeder.
The apparatus is particularly well suited for use in placement machines for mounting electronic components on circuit boards. Such machines generally have a series of feeder slots for holding component feeders, and a picking device constructed to pick components from the feeder slots for mounting to a circuit board.
According to another aspect of the invention, a package of electronic components includes a housing adapted to be inserted into a component feeder of a placement machine, a multiplicity of electronic components contained within the housing and arranged to be sequentially picked from the package by the placement machine, and a removable label affixed to the package. The removable label has an adhesive backing for remounting the label, after removal from the package, on a component feeder, and light-scannable information printed thereon for identifying the components of the package. Preferably, the package has a multiplicity of such removable labels, for multiple remountings of the package on different feeders.
According to another aspect of the invention, a method for monitoring the configuration of component feeders in a placement machine having a series of feeder slots for holding the component feeders is provided. The method includes scanning, while the machine is in process of picking a component from a given feeder slot, a slot marker corresponding to the given slot and a feeder marker corresponding to the component feeder in the given slot. The method also includes comparing configuration information gathered by the scanning with stored information to check for configuration errors.
Preferably, the steps of scanning and comparing are performed while the machine is placing components.
In some embodiments, the method also includes alerting an operator upon detection of an undesirable arrangement of slot markers and feeder markers.
Prior to the operation of the placement machine, the method may also include installing component reels in feeders, scanning reel labels and feeder labels of their associated feeders to identify which components are loaded on which feeders, and mounting the loaded feeders on the placement machine.
The invention can reduce the chance of component loading error by continuously checking the arrangement of component feeders on a placement machine and alerting the operator before a mistaken component is placed. Advantageously, the system does not require the machine to sit idle while component arrangement is checked. In addition, the invention can provide accurate component inventory information and track individual feeder use for maintenance purposes. The basic components of the system are readily installed on conventional placement machines.
Other features and advantages will also be apparent from the following description and drawings.